Phacoemulsification Needle

ABSTRACT

A phacoemulsification needle having a hollow passageway terminates in a straight needle tip formed off-axis from the passageway, allowing the needle tip to move eccentrically when the needle is subjected to torsional or longitudinal vibratory motion. The tip may be flared or may be coextensive with the needle body. The aspiration passageway formed through the needle body may be formed off-axis from the needle body axis. The tip may also be angled with respect to the needle body. The inner and outer surfaces of the needle tip are roughened, as by sandblasting, to enhance the cutting effect of the tip when used with a non-longitudinal handpiece. The lip of each needle tip is polished to a high degree of smoothness and the edges of the tip are rounded to lessen the incidence of snags or cuts.

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/263,315, filed 31 Oct. 2008, and claims priority from U.S.Provisional Patent Application Ser. No. 61/150,320, filed 6 Feb. 2009,both of which are incorporated herein in their entirety by reference.

FIELD OF THE INVENTION

This disclosure relates to surgical instruments and surgical techniquesused in eye surgery and more particularly, to phacoemulsificationapparatus and methods for their use.

BACKGROUND OF THE INVENTION

A common ophthalmological surgical technique is the removal of adiseased or injured lens from the eye. Earlier techniques used for theremoval of the lens typically required a substantial incision to be madein the capsular bag in which the lens is encased. Such incisions wereoften on the order of 12 mm in length.

Later techniques focused on removing diseased lenses and insertingreplacement artificial lenses through as small an incision as possible.For example, it is now a common technique to take an artificialintraocular lens (IOL), fold it and insert the folded lens through theincision, allowing the lens to unfold when it is properly positionedwithin the capsular bag. Similarly, efforts have been made to accomplishthe removal of the diseased lens through an equally small incision.

One such removal technique is known as phacoemulsification. A typicalphacoemulsification tool includes a handpiece to which is attached ahollow needle. Electrical energy is applied to vibrate the needle atultrasonic frequencies in order to fragment the diseased lens into smallenough particles to be aspirated from the eye through the hollow needle.Commonly, an infusion sleeve is mounted around the needle to supplyirrigating liquids to the eye in order to aid in flushing and aspiratingthe lens particles.

It is extremely important to properly infuse liquid during such surgery.Maintaining a sufficient amount of liquid prevents collapse of certaintissues within the eye and attendant injury or damage to delicate eyestructures. As an example, endothelial cells can easily be damagedduring such collapse and this damage is permanent because these cells donot regenerate. One of the benefits of using as small in incision aspossible during such surgery is the minimization of leakage of liquidduring and after surgery and the prevention of such a collapse.

Phacoemulsification needles and tips are well represented in the priorart. Needles and tips of varying configurations are well known. Aparticular shape for a tip or needle is often dictated by the type ofhandpiece with which the needle is to be used.

U.S. Pat. No. 5,725,495 (Strukel et al) teaches and describes aphacoemulsification handpiece, sleeve and tip illustrating a widevariety of tip configurations and needle cross-sectional configurations.

U.S. Pat. No. 6,007,555 (Devine) teaches and describes an ultrasonicneedle for surgical emulsification. The needle and its tip are shown inboth circular and oval configurations.

U.S. Pat. No. 6,605,054 (Rockley) teaches and describes a multiplebypass port phacoemulsification tip having multiple aspiration ports anda single discharge port to infuse liquid into the eye.

U.S. Pat. No. 5,879,356 (Geuder) teaches and describes a surgicalinstrument for crushing crystalline eye lenses by means of ultrasoundand for removing lens debris by suction which demonstrates the use of asleeve positioned concentric to the needle and having a pair ofdischarge ports formed thereon.

U.S. Pat. No. 5,645,530 (Boukhny) teaches and describes aphacoemulsification sleeve, one variation of which has a bellows portionattached to a discharge port ring which directs an annular flow ofliquid around the needle and into the eye. The use of the bellows isintended to allow the sleeve to absorb spikes in liquid pressure duringthe operation.

Published U.S. Patent Application No. 2003/0004455 (Kadziauskas) teachesand describes a bi-manual phacoemulsification needle using separateemulsification and aspiration needles inserted into the eyesimultaneously during surgery.

Published U.S. Patent Application No. 2006/0217672 (Chon) teaches anddescribes a phacoemulsification tip that is swaged or crimped at itsdistal end. The tip is intended for use with a handpiece producingtorsional motion and the crimping forms cutting edges at the distal end.

Many phacoemulsification needles and tips are designed for use withhandpieces that vibrate the needle longitudinally at relatively lowfrequencies. In addition to longitudinal vibration, the NeoSoniX®handpiece sold by Alcon, Inc. of Ft. Worth, Tex. has a rotational ortorsional oscillation vibration frequency of about 100 cycles/second.There are also handpieces that provide torsional oscillation of thephacoemulsification tip at frequencies of about 32,000 cycles/second.

Use of the torsional-type handpiece has called for phacoemulsificationneedle tip designs differing from those used with the longitudinal-typehandpiece. For example, needles have been designed with tips that areshaped, swaged and angled to take advantage of the torsional motioncreated by the handpiece.

Many surgeons favor phacoemulsification needles having the straight tipdesign most commonly used with longitudinal handpieces but have foundthat using them with torsional handpieces does not produce good results.

I have found that forming the needle tip in an off-axis positionrelative to the axis of the needle body causes sufficient eccentricmotion, or “wobble” during torsional motion to produce improvedphacoemulsification results while retaining the straight-tipconfiguration. Forming the needle body in an asymmetric configurationalso produces useful “wobble”. I have also determined that use of anoff-axis needle tip or needle body improves performance when the needleis used in a non-longitudinal type of handpiece, such as in thetorsional mode or the elliptical mode.

In accordance with a preferred embodiment of the apparatus aphacoemulsification needle is provided for use with a high-frequencytorsional phacoemulsification handpiece with the needle having astraight needle tip with the tip being formed off-axis with respect tothe hollow passage formed through the needle.

In accordance with another preferred embodiment, the needle body isformed with an off-axis central aspiration passageway, a centralaspiration passageway with a cross-sectional shape different from thatof the needle body, or a combination of these configurations, andcombined with a standard or an off-axis needle tip.

While the following describes a preferred embodiment or embodiments ofthe present invention, it is to be understood that such description ismade by way of example only and is not intended to limit the scope ofthe present invention. It is expected that alterations and furthermodifications, as well as other and further applications of theprinciples of the present invention will occur to others skilled in theart to which the invention relates and, while differing from theforegoing, remain within the spirit and scope of the invention as hereindescribed and claimed. Where means-plus-function clauses are used in theclaims such language is intended to cover the structures describedherein as performing the recited functions and not only structuralequivalents but equivalent structures as well. For the purposes of thepresent disclosure, two structures that perform the same function withinan environment described above may be equivalent structures.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the present invention will be best understood byreference to the accompanying drawings in which like numbers are used toidentify like parts, and which are presented to illustrate the aspectsof the invention although not necessarily to actual scale, wherein:

FIG. 1 is a drawing showing prior art straight oval- and square-shapedtips;

FIG. 2 is a drawing showing several prior art needle cross-sectionalconfigurations;

FIG. 3 is a lateral schematic view of a phacoemulsification needleembodying the present invention;

FIG. 4 is a partial lateral view of the needle tip of FIG. 3;

FIG. 5 is a view taken along 5-5 of FIG. 4;

FIG. 6 is a lateral schematic view of a second phacoemulsificationneedle embodying the present invention;

FIG. 7 is a lateral view the needle tip of FIG. 6;

FIG. 8 is a view taken along 8-8 of FIG. 6;

FIG. 9 is a partial lateral view of a variation of the tip shown in FIG.3;

FIG. 10 is a partial lateral view of a variation of the tip shown inFIG. 6;

FIG. 11 is an illustration of the end of a prior art straight needle tipduring torsional motion; and

FIG. 12 is an illustration of the end of a needle tip constructed inaccordance with the present invention and used with torsional motion;

FIG. 13 is a bottom view of FIG. 12;

FIG. 14 is an illustration of the end of a prior art straight needle tipduring torsional motion;

FIG. 15 is an illustration of the end of a needle tip constructed inaccordance with the present invention and used with torsional motion;

FIG. 16 is an end view showing a needle having a triangular offset tip;

FIG. 17 is an end view of a needle having a pentagonal offset tip withthe aspiration passageway formed at an apex to adjacent sides of thepentagon;

FIG. 18 is a view of FIG. 17 showing the aspiration passagewaypositioned along one side of the pentagonal tip;

FIG. 19 is an end view of a square tip showing the aspiration passagewaypositioned at an apex of two adjacent sides of the square;

FIG. 20 is an end view of a square tip extending from a needle bodyhaving a circular outer cross-section and an aspiration passageway withan oval cross-section;

FIG. 21 is a lateral sectional view of a portion of a straight, unflaredphacoemulsification needle having a circular exterior cross-sectionshape and an internal aspiration passageway having an ovalcross-sectional shape;

FIG. 22 is an end view of the needle of FIG. 21;

FIG. 23 is a lateral sectional view of a portion of a straight, unflaredphacoemulsification needle having an oval cross-sectional shape with anaspiration passageway having a circular cross-sectional shape and offsettoward one end of the needle body;

FIG. 24 is an end view of the needle of FIG. 23;

FIG. 25 is a lateral view of a phacoemulsification needle with an angledtip formed off-axis to the needle body;

FIG. 26 is a view along 26-26 of FIG. 25;

FIG. 27 is an enlarged view of a flared phacoemulsification needle tip;

FIG. 28 is an enlarged view of FIG. 27;

FIG. 29 is a microscopic view of a portion of the outer surface of thetip of FIGS. 27 and 28 after roughening and polishing; and

FIG. 30 is a microscopic view of a portion of the inner surface of thetip of FIGS. 27 and 28 after roughening and polishing.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, the numeral 10 indicates generally a prior artphacoemulsification needle tip as shown in U.S. Pat. No. 6,007,555.Needle 10 terminates in a mouth 12 defined by a lip 14 at the end ofneedle body 16, with lip 14 and needle body 16 formed as having an ovalcross-section configuration.

Referring to FIG. 1, the numeral 18 indicates generally a prior artphacoemulsification needle tip from U.S. Pat. No. 6,007,555, having amouth 20 defined by a lip 22 at the end of needle 24. Thecross-sectional configuration of needle 18 and mouth 20 is a rectangle.

Referring now to FIG. 2, the numeral 26 identifies several prior artphacoemulsification needles as described in U.S. Pat. No. 5,725,495,with needle 28 having a circular cross-section as shown at 30, needle 32having a triangular cross-section as shown at 34 and needle 36 having anoctagonal cross-section as shown at 38.

Both tips 10 and 18 in FIG. 1 exemplify one form of a “straight” needletip, that is, a tip that is coaxial with or centered on the hollowaspiration passageway formed through the needle body. Other straighttips are known which have needle tips that are flared, that is, largerin cross-sectional area than the needle's aspiration passageway yetwhich are centered on the passageway.

Referring now to FIG. 3, the numeral 40 indicates generally aphacoemulsification needle embodying certain aspects of the presentinvention. Needle 40 has a needle tip 42 formed integrally with a hollowneedle body 44 at a distal end thereof. At a proximal end thereof,needle body 44 has a needle end 46 which terminates in a mount 48 whichallows needle 40 to be attached to a phacoemulsification handpiece. Inthe example shown, needle body 44 has a circular cross-section with alongitudinally-extending central axis 50.

Referring to FIG. 4, an enlarged detail of tip 42 is shown. As seen inboth FIGS. 4 and 5, tip 42 has a mouth 52 defined by a lip 54 which, inthe example shown in FIGS. 3 and 4, is formed at a 30° angle 146 to axis50. The angle shown is one of choice: lip 54 can also be formedperpendicular to axis 50 or any number of other configurationscorresponding generally to the configurations of known straight tipspresently used with longitudinally-vibrating hand pieces.

As viewed in FIG. 4, tip 42 has a lead portion 56 and a trailing portion58, with lead portion 56 being that part of lip 54 that extendslongitudinally forward past trailing portion 58, while trailing portion58 is that part of lip 54 that extends the least distance forward. Inthe example shown in FIG. 4, trailing portion 58 is substantiallycoextensive with the outer surface 60 of needle body 44, while leadportion 56 is offset by a distance 62 from the outer surface 60 ofneedle body 44. The effect of forming lip 54 at the angle shown is toplace lead portion 56 at the farthest point from needle body axis 50.

Referring now to FIG. 5, the aspiration passageway 64 of needle body 44is shown to illustrate the position of axis 50. Tip mouth 52 is showndefined by lip 54 with lead point 56 and trailing point 58. In theexample shown, tip 42 has a circular cross-section having its owncentral tip axis 66 extending therethrough. As seen in FIGS. 4 and 5, inthis example, axes 50 and 66 do not coincide but are offset by adistance 68. As also seen in FIG. 5, the cross-sectional area of tip 42is larger than the cross-sectional area of needle body 44 when viewed ina plane perpendicular to axis 50.

In a preferred example needle body 44 is 1.0 mm in exterior diameterwith a wall thickness of 0.10 mm, leaving an interior diameter of 0.80mm. Tip 42 has an exterior diameter of 1.10 mm and a wall thickness of0.10 mm. The lateral distance from the point at which tip 42 begins toenlarge outward from needle body 44 to lead point 56 is 1.80 mm, whileoffset distance 62 is 0.30 mm.

Referring now to FIG. 6, a second example of a needle tip formed onneedle 40 is shown, embodying certain aspects of the present invention.Needle tip 70 is square in cross-sectional shape and is formedintegrally with a hollow needle body 72. In the example shown, needlebody 72 has a circular cross-section with a longitudinally-extendingcentral axis 74.

Referring to FIG. 7, an enlarged detail of tip 70 is shown. As seen inboth FIGS. 7 and 8, tip 70 has a mouth 76 defined by a lip 78 which, inthe example shown in FIGS. 6 and 7, is formed at a 30° angle 148 to axis74. The angle shown is one of choice: lip 78 can also be formedperpendicular to axis 74 or any number of other configurationscorresponding generally to the configurations of known straight tipspresently used with longitudinally-vibrating hand pieces.

As viewed in FIG. 7, tip 70 has a lead lip portion 80 and a trailing lipportion 82, with lead portion 80 being that part of lip 78 that extendslongitudinally past trailing portion 82, while trailing portion 82 isthat part of lip 78 that extends the least distance longitudinallyforward. In the example shown in FIG. 7, trailing lip portion 82 issubstantially coextensive with the outer surface 84 of needle body 72,while lead lip portion 80 is offset by a distance 86 from the outersurface 84 of needle body 72. The effect of forming lip 78 at angle 148is to place lead lip portion 80 farthest from needle body axis 94.

Referring now to FIG. 8, the aspiration passageway 64 of needle body 72is shown, with central axis 74. Mouth 76, defined by lip 78, has a firstslanted lip portion 88 extending from lead point 80 to trailing point82, and a second slanted lip portion 90 disposed opposite lip portion 88and also extending from lead portion 80 to trailing portion 82. In theexample shown, tip 70 has a square cross-section having its own centralaxis 92, which, as seen in FIGS. 7 and 8 is offset from needle body axis74 by a distance 94. As also seen in FIG. 8, the cross-sectional area oftip 70 is greater than the cross-sectional area of needle body 72 whenviewed in a plane perpendicular to axis 74.

Referring now to FIG. 9 the numeral 94 identifies a phacoemulsificationneedle constructed substantially as described with respect to FIGS. 3, 4and 5. Needle 94 has a tip 96 formed with a circular cross-section andintegral with needle body 98. Needle body 98 has a central axis 100.

Tip 96 has a circular mouth 102 which, in this example, is formed at anangle 104 to axis 100. In this example, angle 104 is measured 30° in adirection opposite to that of angle 146 of mouth 52 as shown in FIG. 4.In this configuration, tip 96 has a lead point 106 and a trailing point108, corresponding in description to points 56, 58 described above. Inthis example, lead point 106 is coextensive with outer surface 110 ofneedle body 98 while trailing point 108 is offset from outer surface 110by a distance 112.

Referring now to FIG. 10 the numeral 114 identifies aphacoemulsification needle constructed substantially as described withrespect to FIGS. 6, 7 and 8. Needle 114 has a tip 116 formed with asquare cross-section and integral with needle body 118. Needle body 118has a central axis 120.

Tip 116 has a square mouth 122 which, in this example, is formed at anangle 124 to axis 120. In this example, angle 124 is measured 30° in adirection opposite to that of angle 148 of mouth 74 as shown in FIG. 6.In this configuration, tip 114 has a lead lip portion 126 and a trailinglip portion 128, corresponding in description to lip portions 78, 80described above. In this example, lead lip portion 126 includes aportion of outer surface 130 of needle body 118 while trailing lipportion 128 is offset from outer surface 110 by a distance 132.

Referring now to FIG. 11, a perspective view of needle 40 is shown, asdescribed above in connection with FIGS. 6, 7 and 8. Needle 40 hasneedle body 72 terminating at one end at tip 70 and at the other end atthreaded mount 48. FIG. 12 is an enlarged perspective view of tip 70showing the square configuration of mouth 76, lip 78 and leading andtrailing portions 80, 82. FIG. 13 is a bottom view of tip 70 showingmouth 76, lip 78 and needle body 72.

The efficacy of having the tip axes in each of the foregoing examples benon-coincident with, or offset from, the needle body axes isdemonstrated in FIGS. 14 and 15. Using a circular tip as an example, thenumeral 134 in FIG. 14 identifies a prior art straightphacoemulsification tip having a circular cross-section defined by mouth136 integral with and centered on needle body aspiration passageway 138.Needle passageway 138 has a central, longitudinally-extending axis 140.The geometry of tip 134 is such that axis 140 is also a central,longitudinally-extending axis for tip 134. When needle body 138 with tip134 is attached to a phacoemulsification handpiece that producestorsional motion about axis 140 the pattern of vibration exhibits littleside-to-side or eccentric motion. In other words, lip 136 tends torotate in a generally uniform motion about axis 140.

Referring now to FIG. 15, tip 42 of FIG. 5 is shown, with circular lip54 and needle body passageway 44 having needle body axis 50 and tip axis66. When tip 42 is subjected to torsional rotation about axis 50 lip 54moves eccentrically, or “wobbles” as it rotates, in part because tip42's rotation is not centered on tip axis 66. This produces movement oflip 54 shown by paths 142 and 144, creating an enhanced cutting oremulsifying effect on the tissue contacted by tip 42. Thus, a straightphacoemulsification needle and tip can be used with a torsionalphacoemulsification handpiece.

The “wobble” effect can be altered by changing the offset distancebetween the tip axis and the needle body axis, and by changing thegeometry of the tip, by using different cross-sectional shapes such astriangular or polygonal.

Referring now to FIG. 16, the numeral 150 identifies aphacoemulsification tip having a triangular cross-sectionalconfiguration terminating at a lip 152 and communicating with a needleaspiration passageway 154 having an axis 156. Tip 150 has a central tipaxis 158 offset from axis 156 by an offset distance 160.

Referring now to FIG. 17, the numeral 162 identifies aphacoemulsification tip having a pentagonal cross-section terminating ata lip 164. Tip 162 communicates with a needle aspiration passageway 166proximate apex 168. Passageway 166 has a central axis 170 and tip 162has a central axis 172 offset from axis 170 by an offset distance 174.

Referring now to FIG. 18, the numeral 176 identifies aphacoemulsification tip having a pentagonal cross-sectional shapeterminating in a lip 178. A needle aspiration passageway 180 extends totip 176 proximate tip wall 182. Passageway 180 has a central axis 184while tip 176 has a central axis 186 offset from axis 184 by offsetdistance 188.

Referring now to FIG. 19, the numeral 190 identifies aphacoemulsification tip having a square cross-sectional shapeterminating in a lip 192. A needle aspiration passageway 194 extends toand joins tip 190 proximate apex 196 of lip 192. Passageway 194 has acentral axis 198 while tip 190 has a central axis 200 offset from axis198 by an offset distance 202.

Phacoemulsification tips embodying the principles of the presentinvention may also be formed on needle bodies that are non-circular incross-section.

Referring now to FIG. 20, the numeral 204 identifies aphacoemulsification tip having a square cross-sectional shapeterminating in a lip 206. Tip 204 extends from a needle body 208 havinga circular cross-sectional shape. Needle body 208 has an oval-shapedneedle aspiration passage 210 having a central axis 212 while tip 204has a central axis 214 offset from axis 212 by an offset distance 216.

As seen in FIG. 20, needle body 208 has an axis 218 that isgeometrically centered even though the distribution of the metal formingthe needle is not uniform about axis 218. Axis 218 is offset from tipaxis 214 by an axis offset 220 and is offset from aspiration passagewayaxis 212 by offset 222. The degree to which tip 204 will wobble will beaffected by the choice of selected offsets 216, 220 and 222.

The foregoing examples have shown tips with flared shapes, that iscross-sectional shapes that are larger in size than the cross sectionalshape of the needle body. Certain principles of the present inventionare also effective for phacoemulsification needles with no flared tipthat is the terminus of the needle is the same cross-sectional shape asthe needle body.

Referring now to FIG. 21, the numeral 224 identifies a straightphacoemulsification needle having a needle body 226 through which anaspiration passageway 228 is formed. As shown in FIG. 22, passageway 228has an oval cross-sectional shape and has a central axis 230. Needlebody 226 has a central axis 232 offset from passageway axis 230 by anoffset distance 234. Needle 224 terminates at an unflared tip 236.

Referring now to FIG. 23, a straight phacoemulsification needle 238 hasa needle body 240 formed with an oval cross-section. As shown in FIG. 24an aspiration passageway 242 is formed through needle body 240 and inthe embodiment shown has a circular cross-section. Passageway 242 has acentral axis 244 and needle body 240 has a central axis 246 offset fromaxis 244 by an offset distance 248. Needle 238 terminates at an unflaredtip 250.

I have also determined that offsetting the tip of an angledphacoemulsification needle tip increases efficiency as compared to asymmetrically fashioned tip. Phacoemulsification needles having flaredtips that are angled with respect to the needle body are known in theart. Heretofore, such tips have been formed such that the bent portionof the needle body met the flared tip such that the tip was symmetricalabout the needle body.

Referring now to FIG. 25 the numeral 252 identifies a portion of aphacoemulsification needle which includes a flared tip 254 and a needlebody 256. Needle body 256 has a longitudinal axis 258 and an aspirationpassageway 260 extending along its length. Tip 254 has an axis 262 thatis centered on the tip opening 264. In this example, the tip has asquare cross-section as best seen in FIG. 26.

A bend 266 is formed on needle body 256 and, as shown in FIG. 25, tip254 is formed with a first wall portion 268 that is coextensive withbend 266 and first needle body portion 270. Tip 254 has a second wallportion 272 that is offset from bend 266 and needle body portion 274.Secondary needle body axis 276 is shown as positioned the same distance278 from first wall portion 268 as the distance 280 axis 258 ispositioned from first needle body portion 270.

Referring now to FIG. 26, an end view of tip 254 is shown takes as aview perpendicular to line 26-26 of FIG. 25. Axes 262 and 278 are shownto offset one from the other by a distance 282. This offset increasesthe eccentric motion exhibited by tip 254 and makes phacoemulsificationmore efficient.

The safety and efficiency of phacoemulsification tips embodying theforegoing aspects of the present invention are enhanced when the innerand outer surfaces of the phacoemulsification tip is roughened, as bysandblasting, and where the lip of the tip mouth is polished to roundthe lip and remove burrs which can damage delicate tissue in the eye,such as the posterior capsule, which may be contacted by the needle tipduring phaco.

The square tip 70 shown in FIGS. 11, 12 and 13 is exemplary of the typeof surfaces to which the roughening process is applied.

As seen in FIG. 12, tip 70 has an upper face 284, a left lateral face286, a lower face 288 and a right lateral face 290. The identifiers“left” and “right” are used here to designate those faces as seen by oneviewing FIG. 12. As can be appreciated, tip 70 has four external faces,all of which are roughened, beginning at and extending away from lip 78.

As further seen in FIG. 12, tip 70 has an inner tip surface 292extending rearward toward needle body 72 and aspiration passageway 64.It is a feature of the present invention that the inner tip surface 292is also roughened, as by sandblasting. The inner and outer surfaces oftip 70 are modified by roughening to create an uneven geometry providingnumerous projections which are engaged by the tissue being emulsified astip 70 is driven in its eccentric, or “wobble” motion.

It is another feature of the present invention to enhance the safety ofthe tips described herein by highly polishing the lip of each. Referringto FIG. 27 the numeral 294 identifies a phacoemulsification needlehaving a flared tip 296 terminating at a lip 298. In the example shown,tip 296 has a circular cross-section but the following descriptionapplies to the various tips of varying geometry described herein. Tip296 is intended to be representative of phacoemulsification tips ascustomarily manufactured. Tip 296 is shown in a magnified view.

A portion of lip 298 is seen in FIG. 28 in a more highly magnified view.The surface 300 of lip 298 is seen to meet tip 296 at substantially aright angle, forming a roughened edge 302. The same configurationcreates a roughened edge 304, formed where lip surface 300 and tip innersurface 306 meet. Tip surface 300 is also characterized by upstandingridges such as those identified by the numeral 308.

Edges 302 and 304, and ridges 308 are somewhat analogous to the“flashing” or “burrs” created when metallic workpieces are cut orsevered. Because of the relatively thin metallic material from whichphacoemulsification needles are formed, such edges and ridges arethemselves thin and sharp, certainly sharp enough to snag corneal tissuewhen a phacoemulsification needle is inserted through a cornealincision. They are also sharp enough to damage delicate eye tissue, suchas the posterior capsule, if the needle tip is brought into contact withthe capsule during surgery.

I have determined that a process of rounding and highly polishing andsmoothing the lips of phacoemulsification needle tips of the typedescribed herein reduces the likelihood that delicate eye tissue will bedamaged during phaco, particularly if the needle is being sued with ahandpiece that produces torsional or elliptical motion.

Referring now to FIG. 29 the numeral 310 identifies the outer surface oftip 296 after a roughening procedure has been performed. As can be seen,surface 310 is “pitted” to create a much larger surface area for contactwith tissue to be phacoemulsified.

FIG. 29 also shows a portion 312 of lip 298 after polishing. Lip surface314 now meets outer surface 310 at a rounded edge 316, much smoother andsnag-free than the roughened edge 302 shown in FIG. 28.

In like fashion, a portion of inner surface 318 of tip 296 is shownafter a roughening procedure has been performed. FIG. 30 also shows aportion 320 of lip 298 after polishing. Lip surface 322 now meets innersurface 318 at a rounded edge 324, much smoother and snag-free than theroughened edge 304 shown in FIG. 28.

The elements of surface finish are described by Quality Magazine(http://www.qualitymag.com/Archives/eacd74ce57c38010VgnVCM100000f932a8c0_)as form, waviness and roughness. These elements, as they are present inthe surface finish on the lips of the needles described herein, arerounded and smoothed to a degree sufficient to avoid the snagging of thetip on tissue in the eye, particularly the tissue through which thecorneal incision is made and the tissue forming the capsular bag.

While the roughening procedure has been preferably described assandblasting, other types of operations to create a controlledlyroughened surface may also be used. In like fashion, other forms ofpolishing or smoothing devices and procedures can also be used tosatisfactorily prepare the lip of each such phacoemulsification needletip.

I claim:
 1. A phacoemulsification needle for use with aphacoemulsification handpiece, said needle comprising: an elongateneedle body having an outer surface, a proximal end and a distal end,said needle body having a central needle axis extending along itslength, said needle body terminating at a lip formed at said distal end;an aspiration passageway extending through said needle body, saidaspiration passageway having a central passageway axis extending alongits length, said aspiration passageway having an inner surface; saidneedle body axis and said aspiration passageway axis being offset onefrom the other such that said needle body axis and said aspirationpassageway axis do not coincide.
 2. The apparatus as recited in claim 1wherein said aspiration passageway has a cross-sectional shape and saidneedle body has a cross-sectional shape, said aspiration passagewaycross-sectional shape being different than said needle bodycross-sectional shape.
 3. The apparatus as recited in claim 2 whereinsaid needle body cross-sectional shape is triangular.
 4. The apparatusas recited in claim 2 wherein said needle body cross-sectional shape issquare.
 5. The apparatus as recited in claim 2 wherein said needle bodycross-sectional shape is hexagonal.
 6. The apparatus as recited in claim2 wherein said aspiration passageway cross-sectional shape is oval. 7.The apparatus as recited in claim 6 wherein said needle bodycross-sectional shape is circular.
 8. The apparatus as recited in claim1 wherein said needle body axis and said aspiration passageway axis areparallel.
 9. The apparatus as recited in claim 1 wherein said lip isrounded and smoothed.
 10. The apparatus as recited in claim 1 wherein atleast a portion of said outer surface proximate said distal end isroughened.
 11. The apparatus as recited in claim 1 wherein at least aportion of said inner surface proximate said distal end is roughened.12. The apparatus as recited in claim 1 wherein at least a portion ofsaid outer surface proximate said distal end and at least a portion ofsaid inner surface proximate said distal end are roughened.
 13. Aphacoemulsification needle for use with a phacoemulsification handpiece,said needle comprising: an elongate needle body having an outer surface,a cross-sectional shape, a proximal end and a distal end, said needlebody having a central needle axis extending along its length; anaspiration passageway extending through said needle body, saidaspiration passageway having a cross-sectional shape and a centralpassageway axis extending along its length; said needle body axis andsaid aspiration passageway axis being offset one from the other suchthat said needle body axis and said tip axis do not coincide; a needletip formed at said distal end, said tip having a cross-sectional shape,an exterior surface and an interior surface, said exterior surface andsaid interior surface terminating at a lip; said tip having a mouthdefined by said lip; said tip having a central longitudinal axis; andsaid tip cross-sectional shape being larger than said needle bodycross-sectional shape.
 14. The apparatus as recited in claim 13 whereinsaid lip is formed at an angle to said tip axis, said lip having a leadportion and a trailing portion, said lead portion of said lip extendinglongitudinally past said trailing portion.
 15. The apparatus as recitedin claim 14 wherein said angle is 30°.
 16. The apparatus as recited inclaim 14 wherein at least a part of said lead lip portion issubstantially coextensive with said needle body outer surface.
 17. Theapparatus as recited in claim 14 wherein at least a part of saidtrailing lip portion is substantially coextensive with said needle bodyouter surface.
 18. The apparatus as recited in claim 14 wherein said tipcross-sectional shape is circular.
 19. The apparatus as recited in claim14 wherein said tip cross-sectional shape is square.
 20. The apparatusas recited in claim 14 wherein said aspiration passagewaycross-sectional shape and said needle body cross-sectional shape aredifferent.
 21. The apparatus as recited in claim 14 wherein said tip isangled with respect to said needle body.
 22. The apparatus as recited inclaim 13 wherein said lip is rounded and smoothed.
 23. The apparatus asrecited in claim 13 wherein at least a portion of said outer surfaceproximate said distal end is roughened.
 24. The apparatus as recited inclaim 13 wherein at least a portion of said inner surface proximate saiddistal end is roughened.
 25. The apparatus as recited in claim 13wherein at least a portion of said outer surface proximate said distalend and at least a portion of said inner surface proximate said distalend are roughened.
 26. A phacoemulsification needle for use with aphacoemulsification handpiece, said needle comprising: an elongateneedle body having an outer surface, a cross-sectional shape, a proximalend and a distal end, said needle body having a central needle axisextending along its length; an aspiration passageway extending throughsaid needle body, said aspiration passageway having a cross-sectionalshape and a central passageway axis extending along its length; a needletip formed at said distal end, said tip having a cross-sectional shape,an exterior surface and an interior surface, said exterior surface andsaid interior surface terminating at a lip; said tip having a centrallongitudinal axis; said tip cross-sectional shape being larger than saidneedle body cross-sectional shape; and a bend formed on said needle bodyproximate said tip such that said tip is angled with respect to saidneedle body axis at least a portion of said tip exterior surface beingnon-coextensive with that portion of said outer needle surface includedin said bend.
 27. The apparatus as recited in claim 26 wherein saidneedle body axis and said aspiration passageway axis are offset one fromthe other such that said needle body axis and said aspiration passagewayaxis do not coincide.
 28. The apparatus as recited in claim 27 whereinsaid needle body cross-sectional shape and said aspiration passagewaycross-sectional shape are different.
 29. The apparatus as recited inclaim 26 wherein said lip is rounded and smoothed.
 30. The apparatus asrecited in claim 26 wherein at least a portion of said outer surfaceproximate said distal end is roughened.
 31. The apparatus as recited inclaim 26 wherein at least a portion of said inner surface proximate saiddistal end is roughened.
 32. The apparatus as recited in claim 26wherein at least a portion of said outer surface proximate said distalend and at least a portion of said inner surface proximate said distalend are roughened.